Microellipsometer with radial symmetry

Qiwen Zhan, James R. Leger

Research output: Contribution to journalArticlepeer-review

123 Scopus citations

Abstract

We report on a novel microellipsometer that uses a spatially filtered high-numerical-aperture (NA) lens for large-angle ellipsometric illumination and high spatial resolution. A radially symmetric ellipsometric signal is achieved with two half-wave plates to produce a pure polarization rotation and a birefringent cube as a radial analyzer. This radial symmetry offers a better signal-to-noise ratio compared with other microellipsometer techniques. Ellipsometric measurement with a spsatial resolution of 0.5 μm is performed with a He–Ne (632.8-nm) laser source and an objective lens with an NA of 0.8. Experimental data on SiO2samples with different thicknesses are in good agreement with spectroscopic ellipsometer results. We acquired ellipsometric images of photoresist microstructure through scanning the sample. Surface profiles of the photoresist microstructure are derived from the ellipsometric data and compared with the results from a stylus profiler.

Original languageEnglish (US)
Pages (from-to)4630-4637
Number of pages8
JournalApplied Optics
Volume41
Issue number22
DOIs
StatePublished - Aug 1 2002

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